The present invention is related to semiconductor device structures which can receive signals via electromagnetic radiation for the purposes of electrical signal control and switching in such semiconductor device structure, and more particularly, to the electromagnetic radiation receiving means in such structures.
The field-effect transistor has certain attributes which are attractive for analog signal switching. The first of these is that a field-effect transistor can be a bilateral device so that, for alternating polarity waveform switching, the field-effect transistor appears to have the same output characteristics whatever the waveform polarities are at which the designated source and drain regions in the device happen to be operated at during any point in a waveform cycle. Further, there is no offset voltage in the source-drain volt-ampere characteristic of a common source operated field-effect transistor as there is in the collector volt-ampere characteristic of a common emitter operated bipolar transistor.
While field-effect transistor devices can have problems concerning the resistance occurring between the effective drain and source when in the "on" condition, and in having sufficient capability to withstand substantial voltages when in the "off" condition, field-effect device structures have been found which are capable of overcoming these problems. Some of these devices are described in the above-reference copending application. These devices include the metal-oxide-semiconductor field-effect transistor (MOSFET) device in various configurations.
Electronic component device theory shows that field-effect transistors are operated by controlling the voltage appearing between the gate thereof and the connection to that one of the two channel regions therein which is effectively serving as the transistor source, or the connection to the substrate. Difficulties arise in those circuits using a field-effect transistor to control power transfers from an alternating polarity power supply because the connections to the channel region of such a transistor serve alternately as the source connections rather than one of them serving continually as the source connection.
A number of electronic circuits have been found for use in controlling the operation of field-effect transistors used as the primary element to control power transfers from an alternating polarity power supply to a load means. However, many of these circuits are inconvenient or expensive to implement or require connections to be made to the gate or substrate of the primary control element field-effect transistor device which negate complete electrical isolation between segments of the control circuitry and the primary power control field-effect transistor device.